J. Peter Lesley was professor of mining at the University of Pennsylvania.
In October 1863 he began a three-month visit to Europe on behalf of
the Pennsylvania Railroad Company, in order to study methods of hardening the surface of
rails (Ames ed. 1909, 1: 436). Lesley reported having met CD at Charles Lyell's
house in London on 21 October 1863, describing him as `a gentle shy
person of 55+ years of age' (ibid. 1: 447). However, Emma Darwin's diary (DAR
242) makes no reference to CD's having gone to London on that date, and records that he
had a `bad day' with `sickness'.